Is this common?  I've heard of some 'dirty' guns experiencing this, but ...  Should it be happening on a brand new, thoroughly cleaned, degreased, and gently lubed pistol?  Even with several different magazines?  

I love the accuracy, I can handle the double action, but I'm not impressed by SIG yet.  I'm willing to give it time, but I hope this is just a fluke.  Although, my dept has had this problem w/ 3 brand new 226R's...

Are the mags reconditoned or used. I had that problem it was the old springs in the mag. I changed them with some Wolff springs from Brownells and it has not missed a bet now. MY gun is a 228 and I use used 226 mags in it from CDNN investment.

My new 226R did this a couple of times. I was using some cheap Remington ammo. The problem is that SIGs are designed to use high pressure match grade ammo. The perform best with good quality ammunition, when you use crap, they just get pissy.

Quoted: My new 226R did this a couple of times. I was using some cheap Remington ammo. The problem is that SIGs are designed to use high pressure match grade ammo. The perform best with good quality ammunition, when you use crap, they just get pissy.

That could be too. Remington does not work good in my Ar 9mm too.

Thanks for the replies.  

Mags - both brand new mags and used mags.  All are factory.

Ammo - American Eagle FMJ (dept isssued)

My partner has a brand new 226R, same ammo, no problems.  I'll try running some federal through it to see if it works.  I'm also switching pistols w/ my partner to see if I'm somehow causing it (Altough my thumb is nowhere near the slide release and I've never limp-wristed a pistol in the past 15 years...)

Might sound stupid but because of the location of the slide catch lever, right handed shooters who are used to a thumb high type grip will often accidently engage this lever after the last shot, causing the slide to return forward again.  I have seen this COUNTLESS times because most shooters who switch to sig have no idea they are doing it.  Also a good friend of mine who is in Charlie Platoon of Seal Team 1, mentioned that his personal 226 when brand new required significant break in before the slide catch engaged the slide with regularity.  Either could be the case.

I had the same problem at first and couldn't figure out what it was, I thought it was the ammo as well, I was using American Eagle FMJ's, but after about 500-600 rounds the problem just went away by itself. It was a little annoying but all around I was so happy with my P226 I overlooked that minor flaw, but now I don't seem to be having that problem anymore and I'm still using the same ammo.

Quoted: Might sound stupid but because of the location of the slide catch lever, right handed shooters who are used to a thumb high type grip will often accidently engage this lever after the last shot, causing the slide to return forward again.  I have seen this COUNTLESS times because most shooters who switch to sig have no idea they are doing it.  Also a good friend of mine who is in Charlie Platoon of Seal Team 1, mentioned that his personal 226 when brand new required significant break in before the slide catch engaged the slide with regularity.  Either could be the case.

I have that very problem with my P239. I use a high, thumbs forward grip on my 1911 and bought the 239 to carry. I'm trying to figure how to change my grip, but the gun doesn't have a lot of extra grip space. Plus, the thumbs forward grip is pretty nailed into muscle memory. I also have that problem with XDs.

Well, after about 900 rounds in 3 days, numerous magazines, and even trying a different pistol, I came to the following conclusion: It must be me!  The slide locks back if I fire one handed, either right or left.  It locks back if a fire two hands w/ weak hand pulling the trigger.  But it doens't lock back when I fire 2 hand strong hand.  I don't see my thumb touching the slide release, but maybe it shifts on recoil.  

I'm going to take about 50 rounds, loaded one per magazine, and fire until I figure this out.  I'll report back what happens.

Thanks for the experience and insight.

U might want to also have someone else try fireing it and see if they get the same reaction, if thats the case, either they are doing the same thing ur doing, or its a malfunction.  Sigs for the most part are very high quality, very reliable guns, the SEALS in the sandbox trust em, so can we.

Quoted: Is this common?  I've heard of some 'dirty' guns experiencing this, but ...  Should it be happening on a brand new, thoroughly cleaned, degreased, and gently lubed pistol?  Even with several different magazines?   I love the accuracy, I can handle the double action, but I'm not impressed by SIG yet.  I'm willing to give it time, but I hope this is just a fluke.  Although, my dept has had this problem w/ 3 brand new 226R's...

This is a common occurance.
http://www.ar15.com/forums/topic.html?b=5&f=14&t=22555
Hot ammo seems to help (+P & +P+)

SIGS run Better "Wet"  

How to get a Sig to function properly:

1- Keep your thumb clear (so that we can officially blame it on the gun)
2- Buy 5 quarts of mobil 1 5w30 motor oil
3- Disassemble Sig.
4- Soak all parts in motor oil
5- Reassemble
6- Dump remaining motor oil all over the Sig
7- Use only +P+ 9mm ammo
8- Replace the brand new mag springs in your mags with brand new Wolff mag springs
9- Put on rain gear, and something to cover your face (cause you're gonna get oil all over you)
10- fire magazine, hope slide locks back.  If it doesnt, go buy another 5 quart jug of oil, and repeat from step 2 on.

After firing 50,000 rounds, your sig should be properly broken in, and will lock back.  But by now you have to replace half the parts anyways, and will have to start over again.

Can you tell how much I love my Sig?

In all seriousness, its a great handgun.  I just cannot get over the fact that in order to get it to work properly, I have to soak the fucker in oil.  None of the other handguns I own require that for something as simple as making a slide lock function...

Actually when i got my 226 it worked like a champ from the first shot, and has not once had a ftf, or fte for that matter, or even a failure to lock, then again i am left handed hehe.   But seriously, i have about 2000 rounds thru it and not a single failure of any kind, im throughly impressed.

Make sure that the slide release is well lubed, all the way deep down inside of the pistol. You may even want to remove the grips and make sure all moving parts have a light coat of oil. I had an issue with a P229 which had worked flawlessly for years and then one day the slide failed to lock back sometimes. Tried many things, including disassembling and cleaning the mags but nothing worked. It turned out that the slide release lever was just a little too dry and would not come up a fraction of a millimeter enough to consistantly let the follower engage the lever all the way up on the last round.

Quoted: How to get a Sig to function properly: 1- Keep your thumb clear (so that we can officially blame it on the gun) 2- Buy 5 quarts of mobil 1 5w30 motor oil 3- Disassemble Sig. 4- Soak all parts in motor oil 5- Reassemble 6- Dump remaining motor oil all over the Sig 7- Use only +P+ 9mm ammo 8- Replace the brand new mag springs in your mags with brand new Wolff mag springs 9- Put on rain gear, and something to cover your face (cause you're gonna get oil all over you) 10- fire magazine, hope slide locks back.  If it doesnt, go buy another 5 quart jug of oil, and repeat from step 2 on. After firing 50,000 rounds, your sig should be properly broken in, and will lock back.  But by now you have to replace half the parts anyways, and will have to start over again. Can you tell how much I love my Sig? In all seriousness, its a great handgun.  I just cannot get over the fact that in order to get it to work properly, I have to soak the fucker in oil.  None of the other handguns I own require that for something as simple as making a slide lock function...

Damn man get a grip. If it does not work right call them and tell them. If your saying something about what I had to do(adding Wolff spring) to my mags, mine were police trade in's, that is why I replaced them now my gun runs 100% . If not , I am sorry you have some many issues with one gun. OUT. Tuna

After about 1100 rounds, it is working - most of the time.  I'll try more lube.  

I knew Marksman would be on this thread like white on rice

My opinion (from someone who's Sigs have never had this happen) is that if your gun is failing to lock back with factory mags, properly lubed, with a grip that doesn't interfere with the slide release, then it should go back to Sig to be made right.  Sig makes very very reliable weapons, and if one isn't working right, not only should they fix it, they want to fix it so that you won't be on a board railing about how your Sig doesn't work (which I would be doing too if I were in your shoes).  Just my .02

LOL.

I don't have any issues anymore, as long as I oil the thing up.  For all the praise I heard about Sig being a great handgun, I was a bit disappointed that something as basic as a slide locking back failed to work correctly.

Aside from the slide lock issues though, here are some facts about Sig.

1- Accurate.  I find my USP's to be very accurate.  I also find my beretta very accurate.  Sig is right there with them.  

2- Fit and finish.  Top notch.  Smooth as butter operation.  Feels good in the hand.  Points as well as my USP, which means I'd be comfortable using it if the SHTF since USP's are my most practiced platform.

3- Smooth DA trigger.  To date, aside from my P2k V3, this is the only DA/SA firearm that doesnt have a cocked and locked mode of carry that I would feel comfortable carrying.  And that my friends says ALOT.

4- I haven't gotten it to fail in a manner that would put my life in jeopardy.  Meaning, no FTF, FTE, FT anything, except lock back.  

5- Problems were curable without having to send to the factory.  Little oil here, little oil there, and it works just fine.  After I run some more rounds through it, I'll ease off the oil and check if it still functions properly.  My guess is it will.

As mentioned before, Sigs tend to like a bit more oil then most pistols. It sometimes screws up people who are used to just dropping a few dabs on a Glock. Keep it oiled up and it will function prefectly. Don't oil it and it will still shoot, but you might have minor problems like mentioned above.